Internal Assessment Resource

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Nov 25, 2013 (3 years and 8 months ago)

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Internal assessment resourc
e Digital Technologies 3.49 for Achievement Standard 91640

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ource is copyright © Crown 2012


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Internal Assessment Resource

Digital Technologies Level 3

This resource supports assessment against:

Achievement Standard 91640

Implement complex techniques in c
onstructing a specified

complex
electronic and embedded system

Resource title:
Lift

4 cr
edits

This resource:



Clarifies the requirements of the Standard



Supports good assessment practice



Should be subjected to the school’s usual assessment quality assurance
process



Should be modified to make the context relevant to students in their school
en
vironment and ensure that submitted evidence is authentic


Date version published by
Ministry of Education

December 2012

To support internal assessment from 2013

Quality assurance status

These materials have been quality assured by NZQA.

NZQA Approved n
u
mber
A
-
A
-
12
-
2012
-
91640
-
01
-
6206

Authenticity of evidence

Teachers must manage authenticity for any assessment
from a public source, because students may have
access to the
assessment schedule

or student exemplar
material.

Using this assessment resource wit
hout modification
may mean that students’ work is not authentic. The
teacher may need to change figures, measurements or
data sources or set a different context or topic to be
investigated or a different text to read or perform.



NZQA
Approved

Internal assessment resourc
e Digital Technologies 3.49 for Achievement Standard 91640

PAGE FOR TEACHER USE

T
his
res
ource is copyright © Crown 2012


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Internal Assessment Resou
rce

Achievement S
t
andard Digital Technologies 91640
:
Implement
complex techniques in c
onstructing a specified

complex
electronic
and embedded system

Resource reference:
Digital Technologies 3.49

Resource title:
Lift

Credits:
4

Teacher guidelines

The follow
ing guidelines are designed to ensure that teachers can carry out valid and
consistent assessment using this internal assessment resource.

Teachers need to be very familiar with the outcome being assessed by Achievement
Standard Digital Technologies
91640
. The achievement criteria and the explanatory
notes contain information, definitions, and requirements that are

crucial when
interpreting the S
tandard and assessing students against it.

Context/setting

This activity requires students to implement complex

techniques to construct and test
an embedded control system for managing the operation of a lift.
Students do not
need to construct a lift shaft and car or the winding system. You could provide a
working mechanical model of this.

This assessment activity

could be used in conjunction with the assessment act
ivity in
Digital Technologies 91639

Develop lift interfaces,

to assess student work in
developing a control system for the lift.
This
s
tandard focuses on developing the
monitoring and control system for
both the hardware and software aspects of the lift
and the functional qualities required
.

The time spent on this task may occur in a number of segments throughout the
project. The project itself may run for
most

of the school year.

You could give the stud
ents a set of specifications, which they use to design and
build their control system for a lift. The whole class makes similar
systems


The
students may negotiate with the teacher whether they will use the equipment
provided or make their own modification
s to it. Alternatively, the students may have
fully established the specifications for their outcome
in prior technological practice

and are ready to make it.

In either case, before they begin to make

their
system


ensure
each student has a set
of specifi
cations for the product, and that
they have

access to an appropriate work
environment and the tools and materials
they will

need to safely make their product.
The specifications need to relate to the monitoring and control of variables in both
hardware and

software, define the functional qualities required, and provide sufficient
scope for the students t
o meet the requirements of the
s
tandard. Make sure that the
electronic environment includes a functional combination of hardware and software.

You will need

to conduct an appropriate teaching and learning programme learning
before beginning this activity.
Provide them with m
ultiple opportunities to practic
e the
complex techniques, and to become familiar with the electronic devices. Students
Internal assessment resourc
e Digital Technologies 3.49 for Achievement Standard 91640

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need to be familia
r with the physical, electronic
,

and software ranges, ratings,
and
interfacing techniques. They need to understand the constraints when these devices
are used in reactive, real time, and phy
sical environments. Ensure
they know how to
write, debug
,

and anno
tate software that can manage a complex electronic and
embedded system correctly.

Before commencing construction, students need to develop and confirm with you a
plan that describes a sound and robust process for developing the
system
.

Students will need
to apply testing throug
hout their construction process

to ensure
that the system is constructed accurately and meets specifications.

Conference with the students and support them as they construct their system, in
case of events that may occur with the equ
ipment or within the computer system and
that are not intended to be part of the task.

Conditions

This is an individual assessment task.

Students will need three to four

weeks of in
-
class time to complete it.

Students should complete all their practical

work in class time.

Students
could
provide evidence across different modes. Ensure that all students
have the opportunity to explain clearly why they did what they did.

Resource requirements

Materials

A simple AA battery pack powered system is recommend
ed to keep cos
t and
complexity to a minimum.

Other materials include:



a microcontroller system, for example,

micro controller, programming set
-
up,
programmer, simulation software, and programming lead. The microcontroller can
be any system that th
e school
is already set up with

and students are familiar with



a prototyping system for testing
, simulation, and debugging, for example,

small
solder
-
less breadboard for testing and trial programming, debu
gging, and/or a
Kiwi
-
patch PCB



a range of input sensors and
devices
depending on specification, for example,

micro switch, LDR, Ird LED and Ird Decoder, and a phototransistor



resistors: 470, 10k, 22k and 4M7 ohm



capacitors: 100nF ceramic, 100uF electrolytic



LEDs: a range of LED for use in circuits for testing and p
roviding in circuit
monitoring and indication test points



piezo sounder to signal actions and alarm states



a range of output devices depending on specification: P
-
9000 motor, Dual drive
multi ratio gearbox, matching wheels, CR servo, H Bridge, and/or BC33
7
transistors



PCB editing and simulation CAD software



a matching PCB machining or etching system



soldering equipment

Internal assessment resourc
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serial/
LCD display to output information



motor gearbox system, servo or a construction set that easily allows a gearing
system to be incl
uded
to manage the speed of the lift


this could be a
construction set that includes all of the above components ready to plug and play,
such as PICAXE kits line
-
following platform.

Other useful resources include:



EAGLE printed circuit board design softwa
re: Cad Soft


http://www.cadsoftusa.com




IR proximity sensors, dc motors
,

and servo motors: Mind Kits


http://www.mindkits.co.nz




Bright Sparks


http://www.brightsparks.org.nz/index.cfm


Students will also need access to sites that provide information relating to the
microprocessor system they are using. For example:



Arduino microcontrollers: Mind Kits


http://www.mindkits.co.nz




Picaxe microcontrollers: Revolution Education


http://www.rev
-
ed.co.uk




LEGO Mindstorms: LEGO engineering


http
://www.legoengineering.com

Additional information

Pl
anning is not assessed in this
s
tandard. However, it is strongly recommended that
students develop a plan to provide a framework for their project to ensure that all the
necessary stages are covered and

sufficient evidence is collected.

Set key milestones as break points where stages can be signed off and evidence is
checked, validated
,

and processed. As a minimum, use a check sheet to make sure
key steps have been closed out, and evidence is gathered an
d validated.

Suppliers of relevant materials include:

Mailtronics Ltd




www.mailtronicsnz.com

Surplustronics



www.surplustronics.co.nz

Electroflash


www.electroflash.co.nz


Internal assessment resource Digital Technologies 3.49 for Achievement Standard 91640

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STUD
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Internal Assessment Resource

Achievement S
t
andard Digital Technologies 91640
:
Implement
complex techniques in constru
cting a specified complex

electronic
and embedded system

Resource reference:

Digital Technologies 3.49

Resource title:
Lift

Credits:
4

Achievement

Achievement with Merit

Achievement with
Excellence

Implement complex
techniques in constructing a
specified
complex
electronic
and embedded system.

Skil
f
ully

implement complex
techniqu
es in constructing a
specified
complex
electronic
and embedded system.

Efficiently implement
complex techniques in
constructing a specified
complex
electronic and
embedded system.

Student instructions

Introduction

This assessment activity requires you
to plan and construct an embedded lift control
system that meets specifications. You do not need to build the lift.

Teacher note:

This assessment activity is based on a lift. You could ada
pt it for
another outcome

such as a conveyer sorting machine or a ca
ble car
.


This is an individual task.

You have three to four

weeks of in
-
class time to complete it.

Teacher note
:

Adapt the time allowed to meet the needs of your students.

You will be assessed on how well you implement complex techniques in constructing
and testing your lift control system to
meet the specifications.


Task

Your teacher will provide a working mechanical model of a lift. Using the model,
construct a control system that manages the operation of the lift to meet
specifications.

Before you be
gin construction, plan out your work, and decide how you will keep
evidence throughout the project of what you did, when you did it, how it worked, and
how you addressed problems. You will not be assessed on your planning
.

Comply with relevant
codes of pra
ctice
,

including
health and safety regulations, in all
your work.

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Specifications

The lift needs to:



move between at least
three

floors, in response to pressing call buttons



prioritise calls to complete the tasks in an orderly fashion



illuminate a display
to indicate that a call is pending



deliver the car at the correct level, as indicated by sensor
s



sound a chime each time it arrives at the correct floor



regulate the speed for safety, efficiency
,

and comfort



incorporate extra input
s

such as overload, speed

regulation current sensing
, fault
indication, automatic maintenance notifications, alarm lock
-
outs
.

Teacher note: Adapt these details as necessary so that they precisely describe
the specifications that your students must meet. You could require students
to
develop these themselves, and confirm their suitability with you.

Process

Follow or adapt this process:



confirm/
agree the plan



choose the main methods/sub
system strategy and design



select the materials



prototype,
function test
,

and debug the sub
systems



record debugging code and testing results, circuits, sketches
,

and circuits



put the sub
systems together and confirm operability



test, debug, fine
-
tune and refine circuits, PCB
,

and program code



build the project



test, prove, evaluate, report, present.

Fina
l submission

Hand in for assessment:



the working lift with software and PCB



debugging and final computer code



annotated
data sheets



annotated
sketches and circuit diagrams
, PCB artwork



debugging and test results



annotated
photographs



video of the lift wor
king



any other evidence of the construction and testing process.

The evidence that you provide should show the following:



the

functional circuits on the PCB must be reliable, with substantially improved
track lay
-
out and soldering



the embedded software mus
t be debugged and modified with code that is in a
well structured, clearly annotated
,

and readily understandable format



the signal and data parameters must be analysed and effectively managed.

Internal assessment resource Digital Technologies 3.49 for Achievement Standard 91640

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Assessment schedule:
Digital Technologies
91640

Lift

Evidence/
Judgements for Achievement

Evidence/Judgements for Achievement
with Merit

Evidence/Judgements for Achievement
with Excellence

The student has
implemented complex techniques
in constructing a specified complex
electronic and
embedded system.

The student h
as produced a lift to meet
specifications with associated input and output
interfacing circuits
.

The student has:



us
ed

PCB (printed circuit board) CAD software
to develop a PCB layout that will preserve signal
integrity

PCB soldering is functional and the

lift operates as
intended.

The PCB layout preserves signal integrity.

For example,

by separating input and output tracks
and board layout and arrangement.



construct
ed
, tested, analysed
,

and modified
functional circuits on PCBs

The student
has
built and te
sted the circuits for the
subsystems
,

correcting where necessary.

Evidence is produced of functional testing of the
circuits and overall project
,

for example:



testing of the inputs and outputs of each
subsystem



the
re is logical response
of the

motor and
L
EDs to the call buttons and position
switches



s
peed control performs correctly.



written and debugged software that can
manage a complex electronic and embedded
The student has skil
l
fully
implemented complex
techniques in constructing a specified complex
electronic and embedded system.

The
student has produced a lift to meet
specifications with associated input and output
interfacing circuits
.

The student has:



constructed, tested, analysed and modified
reliable circuits on PCB, with impr
oved track
layout and soldering


The PCB layout is impr
oved
,
for example
,

by
:



using a number of PCBs



matching PCB track width to signal, p
ower
outputs
,

and power DC rails




taking care
with track spacing and location




c
orrectly dimensioni
ng components to fit
PCB neatly




clean and tidy soldering of PCB with
s
mo
oth secure soldered connections




organised and secure
d

wire runs to
sensors and motors.



written, debugged and annotated readily
understandable software that can manage a
complex electronic and

embedded system

The student has written readable, well
-
forma
tted
,

and clearly annotated code

The student has tested and debugged the program
to ensure that it functions correctly and as
intended on a sample of expected operating
The student has efficiently
implemented complex
techniques in constructing a specified complex
electronic and embedded system.

The student has

produced a lift to meet
specifications with associated input and output
interfacing circuits
.

The student has:



constructed, tested, analysed and modified
reliable functional circuits on PCB, with
substantially improved track layout and
soldering

The PCB l
ayou
t is substantially improved, for
example
,

by:



using double
-
sided PCB with ground plane



using surface mount devices (SMD)



using connector plugs, header strips,
ribbon cables
.

Software is well structured and documented.

Extended commands have been used.



written, debugged and modified well
-
structured,
clearly annotated, and readily understandable
embedded software

The student has written readable, well
-
formatted
,

and clearly annotated code.

For example:



several versions of the program have been
developed



effective use has been made of macros,
sub
r
outines,

library functions (such as

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system


The student has written and debugged the code to
ensure that the lift functions as inten
ded.



analysed and managed signal and data
parameters

The student will have considered how the lift
responds to call button presses while consid
ering
its present position (such as

floor level and in
transit).

For example, requirements for trapping

and stor
ing
multiple

input data while in transit
.

This description relates to only part of what is
required, and is indicative only
.


conditions.

For example,

multiple calls,

overload,

and the
sequence it generates in re
sponse to button
activation
.



analysed and improved management of signal
and data parameters

For example,

multiple calls

(more than one button
being pressed on the lift at one time), overload,

and the actions

generated in response to these
conditions.

For
example,

with
o
verload issues
,

if the lift is
going to be over
loaded the student will analyse

the
readings from the overload sensors to determine
the difference between average and overload
conditions. The student will then set operating
limits or threshol
ds to function as specified.

This description relates to only part of what is
required, and is indicative only.



motor speed control
,

library call)



c
alls to subroutines
,

library linked code
that communicate with advanced digital
sensors using I2C and specialised digital
formats



m
acros or
subroutines are used to scale
values, store data,
and
transmit data to
local LCD or remote digital

monitoring and
de
bugging systems.



analysed and effectively managed signal and
data parameters

Software techniques such as averaging, dynamic
thresholds are
used to overcome problems such
as noisy, fluctuating signals, 50Hz light flicker,
contact bounce etc.

F
or example
,

the student analysed

the readings
from the overload

sensor using debug o
r serial text
to determine the
difference b
etween a normal
operating
load
and an overload. They then built
thresholds into their programme to allow for safe
operating.

T
he student checked that the pro
gramme was
monitoring

the limit switch often enough to
guarantee detection of the elevator
.

This description relates to only
part of what is
required, and is indicative only.


Final grades will be decided using professional judgement based on a holistic examination of the evidence provided against th
e criteria in the
Achievement Standard.